Bouncer animation

More obvious animation where bouncer position is influenced
by touches.

Test: Pull up bouncer, press back button
Test: Pull up bouncer, unlock with fp
Test: Unlock with fp with bouncer hidden
Test: Unlock with SmartLock
Test: Ask for auth on top of FLAG_SHOW_WHEN_LOCKED activity, press back
Test: packages/SystemUI/tests/src/com/android/systemui/statusbar/phone/ScrimControllerTest.java
Fixes: 3699775
Change-Id: I016dfa17f17571261691669c82385d2d844c5917